The field of the disclosure relates generally to noise reduction for rotary machines, and more particularly to a noise baffle for an intake section of a rotary machine.
At least some known rotary machines include silencers in an air intake section to reduce an amount of noise generated by the rotary machine. At least some known silencers include baffles that contain an effective sound absorbing material. However, at least some of the more effective sound absorbing materials do not completely vaporize at an operating temperature of the rotary machine. Thus, at least some such sound absorbing materials present a risk of forming deposits containing calcia, magnesia, alumina and silica (CMAS deposits) in a hot gas path of the rotary machine if such sound absorbing materials escape from the baffle. CMAS deposits may degrade performance of the rotary machine through, for example, spallation of thermal barrier coatings, plugging of cooling circuit holes, accumulation on areas that are impingement cooled, and other effects.
In addition, at least some known baffles include the effective sound absorbing material wrapped in a fiberglass cloth to inhibit escape of the sound absorbing material into the hot gas path. However, in at least some cases, the fiberglass cloth is not one hundred percent effective in preventing escape of the sound absorbing material from the baffle.